docs: def setup_sdk_logging(logfile=None, loglevel=logging.INFO):
      """
      Setup a NullHandler to the root logger. If ``logfile`` is passed,
      additionally add a FileHandler in ``loglevel`` level.
  
      Args:
          logfile(str): A path to setup a log file.
          loglevel(int): :mod:`logging` log level.
  
      Returns:
          None
      """
  
      logging.root.setLevel(logging.DEBUG)
      logging.root.addHandler(logging.NullHandler())
      if logfile:
          fh = logging.FileHandler(logfile)
          fh.setLevel(loglevel)
          fh.setFormatter(get_default_log_formatter())
          logging.root.addHandler(fh)